[petsc-dev] [petsc-maint #89809] 3D DMDAs in petsc-3.2

[Barry Smith]

  Rich,

     As a temporary fix edit da3.c and remove all the lines that have /* 2d case */ in them.

   Barry

On Oct 10, 2011, at 4:12 AM, Richard Katz wrote:

>> summary:     cruft to handle the special case of solving a 2D problem in a 3D algorithm with stencil size > 1.  This only works in the 3D case, z-dimension
> 
> This sounds rather suspicious to me.
> 
>> the second layer of ghost points uses the first layer instead of getting the second layer.
> 
> I think this may be what is causing a problem in my code:
> 
> (gdb) n
> 28        ierr = DMDAGetGridInfo(user->dav,&is,&js,&ks,&ie,&je,&ke,0,0,0,0);CHKERRQ(ierr);
> (gdb) print ks
> $1 = 0
> (gdb) print ke
> $2 = 7
> (gdb) print v[8][5][5].u
> $5 = 0.071731334082415735
> (gdb) print v[7][5][5].u
> $6 = 0.071731334082415735
> 
> it seems to only occur on the k+ processor boundary (when the next processor is in the k+ direction)
> 
> Cheers
> Rich
> 
> 
> 
> 
> 
>> 
>> Since I don't understand your /* 2d case */ business I leave it to you to fix
>> 
>> I don't understand it either and haven't tried. Maybe Ethan can take a look.
>> 
> 
> ________________________________
> Richard Foa Katz
> Dept Earth Sciences, Univ Oxford
> http://foalab.earth.ox.ac.uk
>